English lesson_relative-pronouns_who-whose-whom-that-which-where

who - whom - whose - that - which - where

We use who for a person, and which for a thing or an idea.
We use that for both a person and a thing/idea.
Whose is a possessive pronoun.
When who is the object, whom, with a preposition, can be used instead, but it is formal and rather old-fashioned.
In modern speech, we use who, or we leave out the pronoun.
Where (relative adverb) refers to places.

Examples of use :

I know a woman. She speaks 6 languages. » I know a woman who speaks 6 languages.
I know a woman. Her husband speaks 6 languages. » I know a woman whose husband speaks 6 languages.
I spoke to a person yesterday. » The person to whom I spoke yesterday (formal)
» The person (who) I spoke to yesterday (informal)
I live in a house. It's 200 years old. » I live in a house which is 200 years old.
That's the hotel. We stayed there last year. » That's the hotel where we stayed last year.
That's the hotel that we stayed in last year.

When can we omit relative pronouns?

Compare :
          - The woman who wanted to see me was a doctor.
           (subject)
          - The woman (that) I wanted to see was a doctor.
             (object)
Relative pronouns can be omitted in the following cases :

          1) When they are the object of relative clauses (as above).
               ex : - The candidate (that) I interviewed was from Japan.

          2) In reported speech :
               ex : - He said (that) Mr. Bell had invented the telephone.

          3) After adjectives :
               ex : - I'm glad (that) you came.
                     - She was surprised (that) he noticed.

                                                           See also : who-whom